1. Field of the Invention
This invention relates generally to processing of pharmaceutical dispensers wherein a processing step involves laser treatment of the dispensers. More particularly, this invention relates to methods and apparatus for providing alternating processing of pharmaceutical dispensers wherein advancement of batches of dispensers through a plurality of laser treatment stations is coordinated with controlling a laser for treating the dispensers in the laser treatment stations.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Some pharmaceutical dispensers are constructed with a wall or membrane surrounding an internal compartment containing the active drug ingredient which, following administration of the dispenser, is released through an opening or openings formed through the wall. The size, shape and location(s) of the opening(s) may vary in accord with the particular requirements of the dispenser. The wall material may itself contain pores which serve as the openings or self-forming pores can arise from the use of certain components within the wall that can be dissolved, leached, eroded or extracted by a fluid environment to thereby permit drug release therethrough following administration of the dispenser. When the wall material does not contain or form openings, however, openings can be formed in a subsequent following administration of the dispenser. When the wall material does not contain or form openings, however, openings can be formed in a subsequent processing step involving mechanical drilling or laser ablation of the wall. Laser ablation may also be used to xe2x80x9cscribexe2x80x9d or mark pharmaceutical dispensers.
Examples of methods and apparatus for laser drilling of pharmaceutical dispensers are described and claimed in the following US Patents, owned by ALZA Corporation: U.S. Pat. No. 4,063,064 and 4,088,864, each of which is incorporated in its entirety by reference herein. In addition, methods and apparatus for laser-forming delivery ports in pharmaceutical dispensers, including non-symmetric multi-layer osmotic dispensers, are claimed and described in U.S. Pat. Nos. 5,658,474 and 5,698,119, owned by Alza Corporation, each of which is incorporated in its entirety by reference herein.
Pharmaceutical dispensers to be treated by a laser are generally continuously advanced along a conveyer path that intersects a laser beam path. The dispensers are treated one at a time by laser energy at a drill site on the dispenser as each dispenser form moves through, or stops within, a laser treatment station in the area of intersection of the conveyer and the laser beam paths. The laser is activated during the time that a dispenser is moving through, or is stationary within, the laser treatment station and is inactivated during the time that the dispensers are advancing into and out of the laser treatment station. Thus, the laser is activated only intermittently, and may, in fact, spend more time inactivated than activated.
It would be an advance in the art to provide methods and apparatus for laser treatment of pharmaceutical dispensers that maximize the time during which the laser is activated to thereby increase the speed, efficiency and cost-effectiveness of laser treatment of pharmaceutical dispensers.
The present invention pertains to providing improved methods and apparatus for treating pharmaceutical dispensers with a laser. The methods and apparatus of the present invention provide significant advantages including a higher dispenser treatment rate, less approach time per treated dispenser and more efficient use of the laser.
The methods and apparatus of the present invention provide for pharmaceutical dispensers to be treated in batches rather than singly. Sequential batches of untreated dispensers are carried on alternate batch carriers that are advanced into associated alternate stationary laser treatment stations. The multiple stationary laser treatment stations are located within a region of adjacency in which a single laser source can be operated to treat alternate batches of dispensers positioned within the associated alternate laser treatment stations. A laser controller directs the laser beam to alternatingly operate in each laser treatment station and, within each laser treatment station, to treat each dispenser in a batch of dispensers positioned therein. An advance coordinator advances the batch carriers in coordination with the activity of the laser controller in a repeating alternating cycle wherein one batch of untreated dispensers is held stationary in position within one laser treatment station (while the laser is operated in the one laser treatment station) during the time that another batch of untreated dispensers is being advanced into another laser treatment station. In this manner, a batch of untreated dispensers is substantially continuously positioned in one or another laser treatment station and the laser is optimally substantially continuously operating to treat dispensers within one or another of the laser treatment stations.
In another aspect, a substantially continuous supply of batches of untreated dispensers is provided to the batch carriers for sequential advancement into the laser treatment stations. Preferably, a dispenser distribution and supply system is provided that permits a supply backlog pressure to develop at on-load stations for each batch carrier. Suitable methods and apparatus for maintaining a substantially constant supply to the alternate batch carriers of the present invention can be provided, for example, with appropriate feedback monitoring and rate coordination logic circuitry provided at strategic locations between a central supply, a supply accumulator and the supply paths for each batch carrier.
The above-described features and advantages, as well as others, will become more apparent from the following detailed disclosure of the invention and the accompanying claims.